Vulnerability · Published Apr 24, 2026 · Assigned by AMZN
CVE-2026-6966Signature Threshold Bypass in awslabs/tough Delegated Roles
Medium 5.3
In plain English
A medium-severity security flaw in tough from AWS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities).
Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.3%top 79.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Improper verification of cryptographic signature uniqueness in delegated role validation in awslabs/tough before tough-v0.22.0 allows remote authenticated users to bypass the TUF signature threshold requirement by duplicating a valid signature, causing the client to accept forged delegated role metadata. We recommend you upgrade to tough-v0.22.0 / tuftool-v0.15.0.
Affected products (as reported)
Weakness: CWE-347 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
References
- https://aws.amazon.com/security/security-bulletins/2026-019-aws/ vendor-advisory
- https://github.com/awslabs/tough/releases/tag/tough-v0.22.0 patch
- https://github.com/awslabs/tough/releases/tag/tuftool-v0.15.0 patch
- https://crates.io/crates/tough/0.22.0 patch
- https://crates.io/crates/tuftool/0.15.0 patch
- https://github.com/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4x third-party-advisory